1. Field
The embodiments relate to a tunnel-type magnetic detecting device using a tunnel magnetoresistive effect (TMR effect).
2. Related Art
Japanese Unexamined Patent Application Publication Nos. 2005-203572, 2003-174217, 2003-299726, and 2002-232035 disclose a spin-valve-type thin film device in which a seed layer of NiFeCr is formed below a magnetoresistive effect part having an antiferromagnetic layer, a fixed magnetic layer, a nonmagnetic material layer, and a free magnetic layer.
It is described in Paragraph [0042] of Japanese Unexamined Patent Application Publication No. 2005-203572 that “It is preferable that the seed layer 33 has a single-layer structure of a magnetic material layer or a nonmagnetic material layer which is preferentially oriented to the (111) plane of a face-centered cubic crystal or the (110) plane of a body-centered cubic crystal. Thereby, the crystals of the antiferromagnetic layer 34 can be preferentially oriented to the (111) plane, and the resistance changing rate of the magnetic detecting device can be enhanced.”
In the tunnel-type magnetic detecting device, in order to improve the MR property typified by the resistance changing rate (ΔR/R), it was important to reduce the surface roughness of an insulating barrier layer while improving the crystal orientation property of each layer.
Generally, a small surface roughness can be improved, for example, if the film thickness of the insulating barrier layer is properly adjusted to some degree. However, there was no probability of obtaining a small surface roughness always stably because it required very severe film thickness control or the like.
The related art does not disclose reducing the surface roughness of the insulating barrier layer as an object of the disclosed embodiments.